A conventional tire lock is disclosed in GB2179607 as shown in FIG. 12, and generally includes an L-shaped body A which has a movable member A1 pivotably connected to one end thereof and a sleeve A2 is mounted to the movable member A1 so as to move the movable member A1. A lock core A3 is located at the connection between the body A and the sleeve A2, such that the sleeve A2 is secured and the body A can lock the tire when the lock core A3 is locked. When unlocking the tire lock, the lock core A3 has to be unlocked and removed from the body A, and the user uses an elongate hand tool to insert into the sleeve A2 and drives the sleeve A2 to extend so as to remove the movable member A1. The lock core A3 has to be removed from the body A and the user has to carry the elongate hand tool, both of which are inconvenient to the user. The hand tool could be lost and cannot unlock the tire lock.
Another tire lock includes a movable rod pivotably connected to the body of the tire lock and a sleeve is mounted to the movable rod. A lock core on the body includes a rotary unit and the sleeve includes a threaded rod threadedly received in the sleeve. The rotary unit includes a driving rod which is inserted into the chamber in the threaded rod. A first protrusion is fixed to the outside of the chamber of the threaded rod and a second protrusion is fixed to the driving rod. The second protrusion includes a second driving member which drives a first driving member on the first protrusion to move the sleeve on the threaded rod. However, there is not any device to cover the body and the sleeve, so damage can happen between the body and the sleeve to unlock the tire lock. Besides, the movable rod is connected to the body in a pivotal manner which is easily damaged, and the trace that the movable rod moves is a curved trace so that the angle of movement is limited and cannot proceed in a wide angular operation, thereby restricting the tire lock from be applied to large size tires.